using System;

using System.Collections.Generic;

using System.Linq;

public static class Program

{

    public static void Main()

    {

        List<Demo> items = new List<Demo> { new Demo{

            Code=1,Message="hello"

        } ,new Demo{

            Code=2,Message="hi"

        }};

        //items=null;

        var result = items.SafeFirstOrDefault();

        Console.WriteLine(result?.Code); // Output: Banana

    }

    public static T SafeFirstOrDefault<T>(this IEnumerable<T> source, Func<T, bool> predicate = null)

    {

        if (source == null)

        {

            return default(T); // Return the type's default value

        }

​

        return predicate == null

            ? source.FirstOrDefault()

            : source.FirstOrDefault(predicate);

    }

    public static T? SafeFirstOrDefault2<T>(this IEnumerable<T>? source, Func<T, bool>? predicate = null)

    {

        if (source == null)

        {

            return default;

        }

​

        return predicate == null

            ? source.FirstOrDefault()

            : source.FirstOrDefault(predicate);

    }

}

public class Demo{

    public int Code{set;get;}

    public string Message{set;get;}

}